This paper is an empirical investigation of the role of the financial sector in the EU Emissions Trading Scheme (EU ETS). This topic is of particular interest because non-regulated entities are likely to have played an important part in increasing the efficiency of the EU ETS by reducing trading transaction costs and providing other services. Due to various reasons (new rules and regulations, reduced return prospects, VAT fraud investigations) banks have reduced their engagement in EU Emissions Trading and it is unclear how this will impact on the functioning of the carbon market. Our regression analysis based on data from the EU Transaction Log shows that large companies and companies with extensive trading experience are more likely to interact with the financial sector, which is why we expect banks’ pulling out of the EU ETS to affect larger companies more significantly. The semi-structured interviews we conducted with representatives of the financial sector, as well as companies liable under the EU ETS, confirm that banks were involved in the EU carbon market in various capacities, specifically as hedging partners for larger companies in the energy sector. Whether this particular role may be taken on by other financial players is unknown at this stage.